''Xanthomonas nasturii'' a

gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...

bacterium Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

that like many other ''

Xanthomonas ''Xanthomonas'' (from greek: ''xanthos'' – "yellow"; ''monas'' – "entity") is a genus of bacteria, many of which cause plant pathology, plant diseases. There are at least 27 plant associated ''Xanthomonas spp.'', that all together infect at l ...

'' spp. bacteria has been found associated with plants, in particular

watercress Watercress or yellowcress (''Nasturtium officinale'') is a species of aquatic flowering plant in the cabbage family, Brassicaceae. Watercress is a rapidly growing perennial plant native to Eurasia. It is one of the oldest known leaf vegetabl ...

(''Nasturtium officinale''). It causes black rot of watercress.

Hosts and symptoms

Symptoms include small yellow or dark leaf lesions around the hydathodes, V -shaped leaf lesions, wilt, distortion of plants and early senescence. Initially the symptoms were attributed to ''Xanthomonas campestris'' due to the similarity of symptoms with black rot of brassicas.

Distribution and economic importance

Watercress is a relatively small crop worldwide, but economically significant for some particular regions of the globe. Black rot of watercress can lower the quality of the watercress and possibly limit yields. It was reported that infections can lead to up to 60% yield reduction and rejection of crops. The disease has been found in samples from the US,

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

and

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

. The disease has been regularly observed in Hawaii production in all islands, mostly during the rainy season from December to April in areas with poor air circulation. This disease has also been found in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

, in

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

and

Portugal Portugal, officially the Portuguese Republic, is a country on the Iberian Peninsula in Southwestern Europe. Featuring Cabo da Roca, the westernmost point in continental Europe, Portugal borders Spain to its north and east, with which it share ...

. It is likely that the disease can be seed transmitted as it has been detected in a seed sample from Spain.

Control

Like for other bacterial diseases, control might involve the use of copper

bactericides A bactericide or bacteriocide, sometimes abbreviated Bcidal, is a substance which kills bacteria. Bactericides are disinfectants, antiseptics, or antibiotics. However, material surfaces can also have bactericidal properties based solely on their p ...

. It is advised to minimize moisture on leaves by reducing overhead irrigation and increasing air circulation.

References

nasturii {{Taxonbar, from=Q62901868 Bacterial plant pathogens and diseases Bacteria described in 2017